Gas tank overpressure after sitting in the sun

Asked by Jun 21, 2016 at 09:11 PM about the 1964 Chevrolet Malibu

Question type: General

I have a 1964 Malibu SS. Not show room quality but I like it. It drives good
and in fair condition.This weekend I filled it up with gas which I don't
normally do just to see how much it would hold.It stopped at about 17
gallons. After it stayed in the driveway for a couple of hours I noticed
something dripping right behind the back tire. It was gasoline dripping from
the frame right next to the gas tank.I went around to the license plate (thats
where the gas cap is) and when I opened the gas cap, about
a quart of gas shot out. It was a very hot day. I siphoned two gallons out
just so that wouldnt happen again.The dripping stopped also. Periodically
throughout the rest of the day I would open the gas cap and relieve
the pressure. I assumed the heat of the day was causing pressure to build
up in the tank.

I checked today and no more dripping. Now, do I have a problem with the
gas cap or the tank? How does the tank normally relieve pressure? Could I
have a hole in the tank and if so where can I take it?

3 Answers

22,635

no vented...cleanout the vent tubes

44,685

Gasoline is stored in underground tanks at about 60 degrees F. If you crammed the tank full and it was hot outside the fuel likely expanded, due to the heat, overflowing the fuel tank. Many of the older cars had vented gas caps, but no sure about yours.

44,685

Fuel when heated will also build pressure to its vapor pressure. If you tank is unvented the buildup in pressure pushed gasoline out of the tank when you took off the gas cap. Do some reading on vapor pressure for gasoline.

Your Answer

Add photo

Related Questions

Malibu

Looking for a Used Malibu in your area?

CarGurus has 81,348 nationwide Malibu listings starting at $995.

ZIP:

Search Chevrolet Malibu Questions

Chevrolet Malibu Experts

#1 tenspeed
tenspeed
Reputation 2,010
#2 T_S_T
T_S_T
Reputation 1,800
#3 Tom Demyan
Tom Demyan
Reputation 1,330
View All

Related Models For Sale

Used Chevrolet Impala
534 Great Deals out of 29,821 listings starting at $799
Used Chrysler 300
347 Great Deals out of 20,484 listings starting at $1,000

Used Cars For Sale

2017 Chevrolet Malibu For Sale
76 Great Deals out of 50,077 listings starting at $12,757
2016 Chevrolet Malibu For Sale
246 Great Deals out of 9,089 listings starting at $11,500
2015 Chevrolet Malibu For Sale
131 Great Deals out of 5,441 listings starting at $8,753
2014 Chevrolet Malibu For Sale
103 Great Deals out of 4,549 listings starting at $8,877
2013 Chevrolet Malibu For Sale
88 Great Deals out of 2,733 listings starting at $5,995